# Thread H3: Is the holographic QEC code structure NECESSARY or CONTINGENT? — literature scout (2026-09-24)

Question: does objection (i) hold? Is the QEC code structure of AdS/CFT forced by any consistent quantum gravity, or is it a contingent feature of this particular duality?

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## VERDICT ON Q1

**CONTINGENT-AT-THE-KILL-CONDITION / NECESSARY-WITHIN-HOLOGRAPHY — objection (i) holds in the part that matters, but H3's literal kill condition is NOT met.**

The one-sentence version: the exact code structure is **provably forced given** the standard holographic area/entanglement prescriptions (Harlow's RT ⇔ QEC theorem, 1607.03901, Thm 1.1, extended by Akers–Penington), so finding "error correction" inside the duality is not evidence of a designer — but **no theorem forces the full code structure on "any consistent quantum gravity,"** the derivation is conditional on the RT-style prescriptions themselves, and a 2026 paper (Terashima) argues the exact holographic QEC structure does not even exist at finite N in ordinary holographic CFTs. Both failure directions (not-forced, not-realized) cut the same way: the code is an emergent/approximate feature of holography's entanglement structure, not a design fingerprint.

## VERDICT ON Q2

**MOVED SUBSTANTIALLY, BUT THE CODE PER SE HAS NOT — objection (ii) has eroded for the information-theoretic core but stands for the specific QEC code structure.**

Positive-Lambda holography is now a working program: static-patch/stretched-horizon holography with concrete models (Susskind's dS-SYK), entanglement-wedge-type prescriptions on cosmological horizons (Shaghoulian; monolayer/bilayer proposals), a derived Hilbert space for dS quantum gravity, and (decisive for the "holography of information" principle) a demonstrated version of holography of information **in asymptotically de Sitter space** (2303.16316, Raju et al., 2023). But as of this search, **no one has demonstrated a holographic QEC code structure for positive Lambda** — the dS literature imports entanglement wedges and extremal surfaces, not subregion codes — and dS/CFT itself retains its original problems (non-unitary dual, complex conformal weights).

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## THE EVIDENCE, PAPER BY PAPER

Marking: **[V]** = verified-at-source (I retrieved the text this session, quote taken from it). **[I]** = inherited-unchecked (training memory or secondary snippet; flagged).

### Q1: Necessary or contingent?

**1. Almheiri, Dong & Harlow, "Bulk Locality and Quantum Error Correction in AdS/CFT", arXiv:1411.7041 [V] — full text retrieved; JHEP 1504:163,2015.**
- Abstract, verbatim: *"We point out a connection between the emergence of bulk locality in AdS/CFT and the theory of quantum error correction."* — "point out a connection," not "derive a structure." Their own framing is interpretive/proposal-language throughout.
- What they ASSUME, their own words (intro, §1, verbatim from full text): *"One shortcoming of our work so far is that, although we have laid out a plausible CFT interpretation of AdS-Rindler reconstruction as quantum error correction, we have ultimately relied on the bulk in deriving this reconstruction. This boils down to the assumption that there exist operators in the CFT that obey the bulk equations of motion and algebra on a subspace. We then use this assumption to perform the Bogoliubov transformation that relates the global and the Rindler reconstructions. This assumption is quite plausible, and essentially follows from the assumed large-N structure of the CFT..."*
- Conclusion, verbatim: *"we have provided what we consider to be a new understanding of how the holographic principle is realized in AdS/CFT."*
- What this means: the QEC reading is an *interpretation* erected on top of the (assumed) bulk dictionary + large-N structure. The code structure is not derived from boundary dynamics alone; it is a reorganization of the standard reconstruction machinery. This is the opposite of "derived from first principles."

**2. Pastawski, Yoshida, Harlow & Preskill (HaPPY), "Holographic quantum error-correcting codes: Toy models for the bulk/boundary correspondence", arXiv:1503.06237 [V] — full text retrieved; JHEP 06 (2015) 149.**
- The sentence they are explicit about being a MODEL, not a derivation — abstract, verbatim: *"We propose a family of exactly solvable toy models for the AdS/CFT correspondence based on a novel construction of quantum error-correcting codes with a tensor network structure."* And in §1: *"In this paper, we propose such a family of exactly solvable toy models of the bulk/boundary correspondence..."*
- Their own list of where the models differ from real AdS/CFT (conclusion, verbatim): *"The behavior of two-point correlators highlights one way our toy models differ from full-blown AdS/CFT... there is no obvious analog of diffeomorphism invariance in a lattice model... A particularly serious drawback of our toy models so far is that we have not introduced any bulk or boundary dynamics."*
- What this means: the ledger's ground (i) cited HaPPY as deriving "the code structure from the entanglement/symmetry structure of the duality" — **that is factually wrong**. HaPPY is an *illustrative construction of what a holographic code could look like* (they "capture key features"), explicitly not a derivation of it. The "exactly solvable" perfect-tensor code is also underdetermined: it is one family among many possible encodings.

**3. Harlow, "The Ryu-Takayanagi Formula from Quantum Error Correction", arXiv:1607.03901 [V] — full text retrieved.** This is the key theorem paper for Q1.
- Abstract, verbatim: *"I argue that a version of the quantum-corrected Ryu-Takayanagi formula holds in any quantum error-correcting code."*
- Theorem 1.1 (their statement, verbatim): *"Say that we have a (finite-dimensional) Hilbert space H = H_A ⊗ H_Ā, a code subspace H_code ⊆ H, and a von Neumann algebra M acting on H_code. Then the following three statements are equivalent: (i) there exists an operator L_A ∈ Z_M ... such that, for any state ρ̃ on H_code, S(ρ̃_A) = Tr(ρ̃ L_A) + S(ρ̃, M) [and the same for Ā with M']; (ii) for any operators Õ ∈ M, Õ' ∈ M', there exist operators O_A on H_A, O'_Ā on H_Ā ... such that O_A|ψ̃⟩ = Õ|ψ̃⟩, O'_Ā|ψ̃⟩ = Õ'|ψ̃⟩ ...; (iii) [equality of relative entropies: S(ρ̃_A|σ̃_A) = S(ρ̃|σ̃, M) ...]."* — i.e. **the RT-formula shape ⇔ subregion-duality/reconstruction ⇔ relative-entropy equality.** Their own gloss: *"This theorem then shows the complete equivalence of the RT formula and subregion duality..."*
- The two caveats that matter for H3 (discussion, verbatim): (a) *"theorem 1.1 ... gives an equivalence between three seemingly different properties ... but it gives no assurance that any of them actually holds."* (b) *"in general we do not expect L_A to have an interpretation as extremizing something (such as the area). This must be a special property of holographic codes."*
- What this means: the theorem is a **conditional necessity** — *given* the RT/area structure, the code structure follows, and vice versa. It does NOT show every consistent quantum gravity has the RT structure. The code is equivalent to the holographic area law, whose status is itself that of a property/conjecture of the duality, not a theorem from first principles. Also note the direction that helps the emergence reading: RT (a known, purely "physical" statement about entanglement) *implies* the code structure — the implementer does no work.

**4. Akers & Penington, "Quantum minimal surfaces from quantum error correction", arXiv:2109.14618 [V]; SciPost Phys. 12, 157 (2022).**
- Abstract, verbatim: *"We show that complementary state-specific reconstruction of logical (bulk) operators is equivalent to the existence of a quantum minimal surface prescription for physical (boundary) entropies. This significantly generalizes both sides of an equivalence previously shown by Harlow; in particular, we do not require the entanglement wedge to be the same for all states in the code space... Our results extend to approximate codes, and even to the 'non-isometric codes' that seem to describe the interior of a black hole at late times."*
- What this means: Harlow's equivalence is robust — it survives (a) state-dependent entanglement wedges, (b) approximation, (c) non-isometric (information-losing) maps. The code⇔area-law equivalence is not a fragile artifact of toy models. But it remains an **equivalence between two sides of holography**, not a theorem that any consistent quantum gravity must instantiate either side.

**5. Dong, Harlow & Wall, "Reconstruction of Bulk Operators within the Entanglement Wedge in Gauge-Gravity Duality", arXiv:1601.05416 [V]; PRL 117, 021601 (2016).**
- Abstract, verbatim: *"In this Letter we prove a simple theorem in quantum information theory, which implies that bulk operators in the Anti-de Sitter / Conformal Field Theory (AdS/CFT) correspondence can be reconstructed as CFT operators in a spatial subregion A, provided that they lie in its entanglement wedge... The proof is a combination of the recent work of Jafferis, Lewkowycz, Maldacena, and Suh on the quantum relative entropy of a CFT subregion with earlier ideas interpreting the correspondence as a quantum error correcting code."*
- What this means: entanglement wedge reconstruction is a **consequence of the quantum-corrected RT formula / JLMS relative-entropy equality**, themselves the core postulates of the duality — not an independent postulate, and not a derivation from "any consistent quantum gravity." The chain is: RT/JLMS (postulate) ⇒ relative-entropy structure ⇒ EWR. Everything hangs off RT.

**6. Cotler, Hayden, Salton, Swingle & Walter, "Entanglement Wedge Reconstruction via Universal Recovery Channels", arXiv:1704.05839 [V]; Phys. Rev. X 9, 031011 (2019).** (Author list per PRX citation page snippet [V-citation, I-name-list from PRX DOI landing snippet].)
- Abstract, verbatim: *"bulk and boundary relative entropies are only approximately equal in bulk effective field theory, and in similar situations it is known that predictions from exact entropic equalities can be qualitatively incorrect. The framework of universal recovery channels provides a robust demonstration of the entanglement wedge reconstruction conjecture..."*
- What this means: EWR survives as a theorem-like statement but only **approximately** — bulk-boundary relative entropies are approximately equal, so recovery is approximate. The exactness that would make the code "designed-looking" is not there; the physics demands approximate recovery with error.

**7. Hayden & Penington, "Learning the Alpha-bits of Black Holes", arXiv:1807.06041 [V]; JHEP 12 (2019) 007.**
- Abstract, verbatim: *"they imply that the bulk reconstruction is necessarily only approximate and allow us to place non-perturbative lower bounds on the error when doing so. Second, they provide a simple and tractable limit in which the entanglement wedge is state-dependent, but in a highly controlled way... black holes provide the first 'explicit' examples of capacity-achieving α-bit codes."* Also: *"we apply a result from the quantum information literature to prove that entanglement wedge reconstruction can be made exact to all orders in 1/N"* (within the code subspace).
- What this means for the necessity question, as asked: the approximate-ness **weakens** the "necessary structure" reading. The exact QEC code picture is not realized in real (black-hole-containing) AdS/CFT; reconstruction is *necessarily* approximate and, for interiors, state-dependent. The structure that survives is a graded, approximate, state-dependent version. (The one code-picture-specific gift here: non-perturbative *lower bounds on reconstruction error* are a genuine prediction of the code framework — see "What this means for H3".)

**8. Faulkner, "The holographic map as a conditional expectation", arXiv:2008.04810 [V].** **Attribution check: the task sheet said "Faulkner & Li" — the paper as retrieved is by Thomas Faulkner alone; "Min Li" appears only in the acknowledgments** (verbatim: *"We thank Chris Akers, Fikret Ceyhan, Netta Engelhardt, Min Li and Pratik Rath"*). Flag for Argus's ledgers: citation as "Faulkner & Li" looks wrong at source.
- Abstract, verbatim: *"We study the holographic map in AdS/CFT, as modeled by a quantum error correcting code with exact complementary recovery... We will start from the assumption of complementary recovery and derive..."* Intro: *"we study exact error correction. There are several known shortcomings to such an exact approach... We comment on how approximate codes can fix these issues."*
- What this means: even the exact-level structural results are derived **from the assumption of complementary recovery** (the code structure is the input, not the output), and the paper itself concedes exact complementary recovery is not a faithful model of holography — approximate codes are needed. Necessity reading: further weakened.

**9. Raju, "Lessons from the Information Paradox", arXiv:2012.05770 [V] — 156-page review; the "holography of information" statement.** (My memory-guessed alternative ID for "the review," 2107.10218, turned out to be a cond-mat double-quantum-dot paper — see "What I could not find".)
- Abstract, verbatim: *"This analysis leads to a broadly-applicable physical principle: in a theory of quantum gravity, a copy of all the information on a Cauchy slice is also available near the boundary of the slice. This principle can be made precise and established — under weak assumptions, and using only low-energy techniques — in asymptotically global AdS and in four dimensional asymptotically flat spacetime."*
- What this means — potentially decisive, and it cuts **against** the strong "necessary" reading of the code: what is generic to *any* theory of quantum gravity (given diffeomorphism invariance) is **information delocalization** ("holography of information") — a *weaker* statement than subregion QEC codes. It says the boundary of a Cauchy slice holds a complete copy; it does not by itself deliver HaPPY-style secret-sharing, multiplicity of equivalent subregion representations, or correctable-region structure. So: gravity forces *redundancy at the boundary*; the *specific code architecture* of AdS/CFT subregion duality is a further, holography-specific structure. The general-gravity part is forced; the code part is not (at least not by this argument).

**10. Chowdhury, Godet, Papadoulaki & Raju, "Holography from the Wheeler-DeWitt equation", arXiv:2107.14802 [V]; JHEP 03 (2022) 019.**
- Abstract, verbatim: *"We show that, even within perturbation theory, any wavefunctional that solves these constraints must have specific correlations between a component of the metric at infinity and energetic excitations of matter fields or transverse-traceless gravitons. These correlations disallow strictly localized excitations. We prove perturbatively that two states or two density matrices that coincide at the boundary for an infinitesimal interval of time must coincide everywhere in the bulk. This analysis establishes a perturbative version of holography for theories of gravity coupled to matter in AdS."*
- What this means: this is the closest thing on the "necessary" side — **holography (boundary delocalization) derived from the Wheeler-DeWitt constraints themselves** (i.e., from diffeomorphism invariance + matter), not assumed. But again: it is holography-of-information, i.e., boundary redundancy — not the subregion QEC code structure. Note also it is done for AdS and (per the 2020 review) flat space; the dS version arrived separately (see Q2).

**11. Terashima, "Entanglement Wedge Reconstruction without Holographic Quantum Error Correction", arXiv:2607.08684 [V] — 2026 preprint, single author (Seiji Terashima, YITP), YITP-26-88, 18 pp; peer-review status unknown as of today.** This is the post-2020 "not forced / not realized" entry, and it is the strongest single item against the necessity reading.
- Abstract, verbatim: *"We argue that this subregion statement should be separated from the stronger holographic quantum error correction interpretation, in which one region-independent logical bulk operator has code-preserving representatives in several boundary regions... An ordinary finite N holographic CFT does not have such a protected invisible sector for supergravity fields. Its low-energy local observables, in particular, suitably smeared stress tensors, detect the physical support and gravitational dressing of ordinary bulk operators... Thus, there is no such holographic quantum error correction and the N=∞ agreement of global and subregion HKLL formulae is a free-theory statement. What remains is entanglement wedge reconstruction without holographic quantum error correction, or subregion complementarity..."*
- Full text (intro, verbatim): *"HaPPY-type codes evade this conclusion because this basic requirement is not satisfied"* (the requirement that the commutant of code-preserving local algebras contains no ordinary bulk operator); *"This argument is not a no-go theorem for subregion reconstruction itself. It rules out only the stronger common-logical-operator interpretation associated with HQEC."*
- What this means: if correct, the exact HaPPY-style code structure is a **toy-model/idealized-large-N artifact**, not the actual structure of a finite-N holographic CFT; what remains is a weaker, region-dependent "subregion complementarity." That is the strongest published-type argument that the code is neither forced nor even real — which is the *opposite* of an implementation fingerprint. Weight with care: one recent preprint, no referee status verified; I did not find corroboration or refutation yet. It is, however, the right kind of challenge for Argus to track.

**Q1 synthesis.** The derivation chain asserted in objection (i) exists but only conditionally: RT/JLMS (postulates of the duality) ⇒ EWR; and RT ⇔ subregion-duality/QEC (Harlow Thm 1.1; Akers–Penington). So *within any holographic theory that obeys the area law*, the code structure is forced, and the implementer is doing no work there. But (a) nothing forces a consistent quantum gravity to be holographic-with-RT in the first place — the general-gravity theorem (WdW) delivers only boundary redundancy, not codes; (b) at finite N the structure is approximate, state-dependent, and per Terashima possibly absent as a code; (c) HaPPY, one of the two papers cited in the ledger, is explicitly a toy model and thus does not even attempt derivation. Both the "not forced beyond holography" and "not exact even in holography" directions agree: the QEC code structure is an emergent, approximate organizing feature of the duality's entanglement structure — not a contingent design object and not a forced universal law.

### Q2: Has de Sitter holography moved?

**12. Strominger, "The dS/CFT Correspondence", arXiv:hep-th/0106113 [V]; JHEP 0110:034,2001.**
- Abstract, verbatim: *"A holographic duality is proposed relating quantum gravity on dS_D... to conformal field theory on a single S^{D-1}... In general the dual CFT may be non-unitary and (if for example there are sufficiently massive stable scalars) contain complex conformal weights."*
- Status: the proposal is 25 years old and its known pathologies (non-unitary, complex weights) are stated in its own abstract. The search found no published resolution; dS/CFT remains a minority route, with the actionable work having moved to static-patch holography.

**13. Susskind, "Entanglement and Chaos in De Sitter Holography: An SYK Example", arXiv:2109.14104 [V].**
- Abstract, verbatim: *"In the first part of this paper the Ryu-Takayanagi prescription, the theory of fast scrambling, and the holographic complexity correspondence are reformulated for de Sitter space. Criteria are proposed for a holographic model to describe de Sitter space. The criteria can be summarized by the requirement that scrambling and complexity growth must be 'hyperfast.' In the later part of the paper I show that a certain limit of SYK is a concrete, computable, holographic model of de Sitter space."*
- This is the static-patch/stretched-horizon program in working form: a concrete dual model, entropy and RT-type prescriptions for dS.

**14. Shaghoulian, "The central dogma and cosmological horizons", arXiv:2110.13210 [V]; JHEP 01 (2022) 132.**
- Abstract, verbatim: *"The fact that the de Sitter bifurcation surface is a minimax surface (instead of a maximin surface) causes problems with this interpretation when trying to import calculations analogous to the AdS case. This suggests anchoring extremal surfaces to the horizon itself, where we formulate a two-sided extremization prescription and find answers consistent with general expectations for a quantum theory of de Sitter space: vanishing total entropy, an entropy of A/4G_N when restricting to a single static patch, an entropy of a subregion of the horizon which grows as the region size grows until an island-like transition at half the horizon size when the entanglement wedge becomes the entire static patch interior, and a de Sitter version of the Hartman-Maldacena transition."*
- What this means: entanglement-wedge-shaped structure (islands, phase transitions, horizon anchoring) has been imported into dS — but explicitly *not* by naive analogy; the minimax/maximin inversion forces new prescriptions. This is entanglement structure for positive Lambda, not QEC codes.

**15. "Bridging the static patches: de Sitter holography and entanglement", arXiv:2305.12861 [V]; JHEP 08 (2023) 074.** (Report no. CPHT-RR018.042023; the abs page render did not show the author line to me — author list unverified, flag.)
- Abstract, verbatim: *"In the context of de Sitter static-patch holography, two prescriptions have been put forward for holographic entanglement entropy computations, the monolayer and bilayer proposals. In this paper, we reformulate both prescriptions in a covariant way and extend them to include quantum corrections. We argue that the bilayer proposal is self-consistent, while the monolayer proposal exhibits contradictory behavior... the entanglement wedge of the screen with the larger quantum area extends and covers the causal diamond between the screens, with a phase transition occurring when the quantum areas of the screens become equal."*
- Status: entanglement-wedge machinery is alive in dS static-patch holography — but it is *prescriptions being tested against each other* (one found inconsistent), i.e., an unsettled, actively developing framework, not a demonstrated "code structure survives Lambda > 0."

**16. Chakraborty, Chakravarty, Godet, Paul & Raju, "Holography of information in de Sitter space", arXiv:2303.16316 [V].** (Author list from the ICTS people-page citation snippet [I for names, V for abstract]; abstract fully retrieved.)
- Abstract, verbatim: *"In a theory of quantum gravity, we demonstrate a version of the principle of holography of information: cosmological correlators in an arbitrarily small region suffice to completely specify the state."* (Also in the paper: the norm on WdW solutions in asymptotically dS, via Faddeev-Popov/gauge-fixing.)
- **This is the decisive Q2 item for Argus**: the specific principle Raju derived in AdS and flat space (2012.05770) has now been **demonstrated in asymptotically de Sitter space** (2023). Objection (ii) — "AdS/CFT is about a spacetime that is not ours" — is thereby retired *for the holography-of-information core*: positive-Lambda quantum gravity still delocalizes information to the boundary. The delocalization is forced by diffeomorphism invariance, not by Lambda's sign.

**17. Chakraborty, Chakravarty & Raju, "The Hilbert space of de Sitter quantum gravity", arXiv:2303.16315 [V]; JHEP 2024, 132 (2024).**
- Abstract, verbatim: *"We obtain solutions of the Wheeler-DeWitt equation with positive cosmological constant for a closed universe in the large-volume limit. We argue that this space of solutions provides a complete basis for the Hilbert space of quantum gravity in an asymptotically de Sitter spacetime... Each functional can be thought of as specifying a 'theory' and, in this sense, the space of solutions is like 'theory space'."*
- This is the first principled Hilbert space for dS quantum gravity — a prerequisite for any future QEC-code statement in dS; none has been made yet.

**18. Shaghoulian & Susskind, "Entanglement in De Sitter space", arXiv:2201.03603 [I]** — cited in the 2305.12861 reference list as *"E. Shaghoulian and L. Susskind, Entanglement in De Sitter space, JHEP 08 (2022) 198 [arXiv:2201.03603]"* and a PURL snippet reads *"The boundary of a static patch is its cosmic horizon."* ID and journal verified as-cited, abstract not fetched this session.

**Q2 synthesis.** Objection (ii) has moved: static-patch holography is now a mature-enough framework with concrete models (SYK), horizon-anchored entanglement wedges with islands (Shaghoulian; monolayer/bilayer), a dS Hilbert space, and — most importantly — holography of information **established in dS** (2023). What has NOT moved: **no QEC code structure (subregion codes, secret-sharing, logical/boundary split) has been demonstrated for positive Lambda in anything I found.** The search for "de Sitter + quantum error correction" returned only AdS-model work (HaPPY-type codes, hyperinvariant tensor networks) and a single unverifiable snippet about a proposed two-time dS duality. So for the code *per se*, objection (ii) still stands; for the underlying delocalization principle, it falls.

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## WHAT THIS MEANS FOR H3 — recommendation, stated plainly

1. **Objection (i) holds in the part that determines evidential value; the ledger's specific factual ground for it is partly wrong.** What is true: the code structure is *derived* from the duality's own physics — Harlow's Thm 1.1 makes RT ⇔ subregion-duality ⇔ relative-entropy an equivalence, Akers–Penington extend it to state-dependent/approximate/non-isometric settings, and it survives there. Finding "quantum error correction" in a holographic theory is therefore what any holographic theory with the area law *must* look like; an implementer adds nothing at that level. What is false in the ledger: HaPPY does not derive the code structure — it proposes (their word, their abstract, their title) *toy models*; ADH explicitly flag that they assume the bulk dictionary and large-N structure rather than deliver it from the boundary. So ground (i) is vindicated in substance (necessity-within-holography) on different evidence than it cited.

2. **The kill condition is NOT met, and now there is evidence cutting the other way.** The kill condition demands necessity from *any consistent quantum gravity*. No such theorem exists: Harlow's theorem is conditional on the RT prescriptions; the only general-gravity derivation (WdW/holography of information) delivers the *weaker* boundary-redundancy property, not the subregion code structure; and Terashima 2026 argues that at finite N the exact code structure is *not even realized* in ordinary holographic CFTs. So the structure is neither forced-by-all-gravity (kill condition fails) nor realized-exactly-anywhere (implementation reading fails). Both failures push the same direction: QEC-in-holography is emergent, approximate, and scheme-dependent — the code picture is a *language for* the entanglement structure, not a *trace of* an encoder.

3. **Net recommendation: do not kill H3 tonight by theorem — but do not raise it either; demote it.** It is not dead because the literal kill condition is unmet and objection (ii) has genuinely eroded (holography of information now holds in dS, and static-patch holography is a live framework — the "our universe" objection is weaker than it was in September 2025). But its diagnosticity for IMPLEMENTATION should fall, because the derivability result (Harlow) is now proved, and because the 2026 no-HQEC argument (if it survives scrutiny) would make the code an even more emergent, less design-like object. The honest credence move: H3's evidential value is close to neutral — emergence predicts the code structure as well as implementation does, and the "approximate/state-dependent/possibly absent" texture is what pure emergence with no designer would look like.

4. **If any part of H3 survives as a live thread, it is these three narrow sub-questions** (keep the raise condition pointed at them, not at the existence of holographic codes):
   - (a) *Code-picture-specific predictions*: Hayden–Penington's non-perturbative lower bounds on reconstruction error, and state-dependence of the entanglement wedge, are predictions the code framework stated in a form the emergence story did not — a "prediction later confirmed" candidate, but weak because they confirm *approximation*, not *design*.
   - (b) *The Terashima claim*: monitor whether "no holographic QEC at finite N" survives refereeing and replicates. If it hardens, H3 collapses into "the code is a large-N idealization," which is maximally emergence-flavored.
   - (c) *dS code structure*: nobody has yet looked for subregion QEC codes in static-patch holography. Finding the *exact* code architecture (secret-sharing, correctable regions) — not just delocalization — in Λ>0 would be the one genuinely contingent, non-emergent-looking discovery available. This is the only direction where H3 could still move the target upward.

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## WHAT I COULD NOT FIND AND WHERE I LOOKED

- **Any demonstration of a holographic QEC code structure in de Sitter / positive Lambda.** Searched: web_search "de Sitter" + "quantum error correction"/"error correcting"/"holographic code", 2022–2025 date filters, plus static-patch variants. Results were all AdS-anchored (HaPPY, hyperinvariant tensor networks 2304.02732, stabilizer graph codes 2209.08954, Brownian SYK codes) or dS papers that do entanglement wedges without codes. The nearest item, "Holography of information in de Sitter space" (2303.16316), delivers delocalization, not codes. A proposed "two-time de Sitter duality" appeared only as a snippet on pith.science with no retrievable arXiv page — unverified, do not cite.
- **The "Faulkner & Li" attribution in the task sheet.** arXiv:2008.04810 as retrieved is authored by Thomas Faulkner alone; Min Li is thanked. If there is a distinct Faulkner–Li paper it did not surface in my searches (arXiv author search not performed — I searched "Faulkner Li holographic" via web_search; nothing else matched).
- **Raju's "Lessons from the Information Paradox" journal placement.** The arXiv listing (2012.05770) shows no journal reference; Raju's own site listing is truncated ("Physics Reports ..."). Not verified beyond arXiv; do not cite a volume number.
- **The exact arXiv ID for Faulkner & Lewkowycz, "Bulk locality from modular flow" (JHEP 2017(7):151).** Existence verified via two independent citation lists (OSTI pages for 1902.02844-era works); the arXiv ID was not fetched — do not quote one.
- **The JLMS arXiv ID** (Jafferis, Lewkowycz, Maldacena, Suh). Referenced by name inside DHW (1601.05416), which I retrieved; I did not fetch JLMS itself. Do not quote an ID.
- **Peer-review status of Terashima 2607.08684 (2026).** It is a fresh preprint (v1 09 Jul 2026); no journal ref on the abs page; corroboration or refutation not found yet. Treat as unrefereed, single-author, but structurally serious.
- **ID-check failures worth logging** (I chased memory-guessed IDs and they were wrong — the exact hazard Argus's methods file warns about): 2107.10218 is not Raju's review — it is "Synchronized coherent charge oscillations in coupled double quantum dots" (cond-mat.mes-hall); 1911.11530 is not a non-isometric-codes paper — it is a CVPR neural-rendering paper (cs.CV). Both verified at source as the wrong papers; the correct items are 2012.05770 (review) and 2109.14618 (Akers–Penington).
- **dS/CFT (Strominger) resolution or disproof.** None found; the route appears simply under-favored, with the field having moved to static-patch holography.

— Thread scout (H3). All quotes above marked [V] were retrieved and copied from arXiv abstract/full-text pages during this session; [I] items are flagged.